wrinkle

A wrinkle-bellied whore; one who has had a number of bastards: child-bearing leaves wrinkles in a woman's belly. To take the wrinkles out of any one's belly; to fill it out by a hearty meal. You have one wrinkle more in your a-se; i.e. you have one piece of knowledge more than you had, every fresh piece of knowledge being supposed by the vulgar naturalists to add a wrinkle to that part.